Polyurethane compositions and their preparation have been investigated intensively throughout the last few decades. These polymer products have proven extremely versatile and are utilized throughout industry. In particular, urethanes which have been applied as soft or hard elastomer coatings or as adhesives and which are either rigid or flexible and in compact or foamed form have found exceptional commercial utility.
Polyurethanes are polymers characterized by repeating carbamic ester groups. They are produced by reaction of polyisocyanate with polyol. This reaction proceeds readily under a variety of conditions, now well-known in the art.
These conditions, as well as many modifiers of the reaction (such as catalysts, surfactants, blowing agents and the like) are described in detail in Polyurethanes: Chemistry and Technology, Vol. XVI, parts I and II of The High Polymers series of Saunders and Frisch, Interscience Publishers (1962 and 1964). These books are incorporated herein by reference as if they were set forth at length.